Cognac and Other Brandy

Distillation

Each parcel of wine used to make cognac is distilled separately, so long as sufficient quantities of wine are obtained. If this is not the case, like parcels are combined and distilled together and the cask is demarcated as coming from diverse sources within a given cru.

The type of still used to make cognac is known as the Charentais alembic. This is composed of a boiler, still head, swan's neck and condenser. Sometimes a wine warmer is added to this structure to increase the throughput, that is, a special device that helps move the distillation process move smoothly along.

The Charentais alembic boiler, which has a capacity of 30 hectoliters, is charged with 25 hectoliters of wine and the wine is heated with gas flame to produce the brouillis (the first distillate), which comes off the still between 40-42° abv. The wine is then heated for an hour and fifteen minutes. When it begins to boil the vapors gather in the still head before passing through the swan's neck to the 75-meter long cooling coil.

The first portion of distillate to come off the still is known as the ‘heads’ and they are discarded. The heads account for 0.5% of the total output of the still. The heart of the brouillis or center of the first distillation is the equivalent of about 9.5% of the base wine. The alcoholic content of the brouillis depends on that of the wine. The final portion following the brouillis off the still is called the tails, and they are discarded as well. Everything left in the wine boiler is called the still wash, which is recycled after being used to clean the inside of the still.

During the second distillation, or la bonne chauffe, the boiler is re-filled with the brouillis, which is brought to a boil and distilled a second time. The heart comes off the still around 72° abv, and is followed by the seconds, also known as the ‘tails’. The seconds are a portion of the distillate which could be aged and used for cognac, but is recycled by most high quality distillers. The heart of the second distillation is referred to as the eaux-de-vie, since it has not yet been aged into cognac. This portion comes off the still at a measured rate of one liter per minute.

The heads and the tails of the second distillation are mixed with the brouillis and re-distilled with the next round in the first distillation, while the seconds or tails of the second distillation are re-distilled with the brouillis in a proportion of three-quarters brouillis to one-quarter seconds. This makes for a more characterful spirit, while adding the seconds back to the brouillis creates a more neutral spirit.

Both cycles together require 24 hours to complete. Nine liters of wine at 9% abv are needed to produce one liter of eaux-de-vie at 71% abv.